Plasma eye drops

Freezing autologous eye platelet-rich plasma (E-PRP) for use as an eye drop preparation can enhance its healing effects for the ocular surface, said Mauro Tiveron Jr MD, a member of the investigational group of Prof Jorge L Alió in VISSUM, Miguel Hernandez University, Alicante, Spain. “Our results indicate that freezing autologous PRP will increase the concentration of important proteins involved in wound healing, maintaining the biological activity in this successful treatment involved in corneal surface tissue regeneration,” Dr Tiveron told the XXXIV Congress of the ESCRS in Copenhagen, Denmark. Dr Tiveron and Prof Alió noted that E-PRP is a blood-derived product that has been used successfully in the treatment of many ocular surface disorders, including dry eye, recurrent corneal erosions and post-LASIK ocular surface syndrome. Its healing effect is attributed to the growth factors and other cytokines synthesised and present in platelets. “Platelets are great reservoirs of growth factors that are contained within their alpha granules. Once activated, the growth factors enhance cell proliferation and wound healing in both soft and hard tissue. These growth factors induce mesenchymal and epithelial cells to migrate and proliferate restoring damaged ocular surface,” said Dr Tiveron. PROCESSING METHODS In their study, Dr Tiveron and the investigational group of Prof Alió prepared PRP as a topical eye drop (E-PRP) using blood from six different healthy volunteers. After a centrifugation the final plasma product was aliquoted for use in four different processing methods. They were preservation of fresh E-PRP at 4-8ºC; freezing E-PRP at -20ºC for three months; spinning the fresh-E-PRP at 6,000rpm and preservation at 4-8ºC; and spinning and freezing the E-PRP. They then used the sandwich ELISA immunoassay (eBioscience/Bender MedSystems) to determine the concentration of fibronectin and several growth factors involved in wound healing, and performed a posterior statistical analysis to determine the differences in platelet and growth factor concentration, Dr Tiveron explained. Their analysis showed that the concentration of platelets was roughly two-fold higher in the prepared E-PRP than in whole blood in all the samples, with mean values of 491.7 cell x 130/μl compared to 265.17 cell x 130/μl. It also showed that there was a positive correlation between the secretion of growth factors for fresh E-PRP. The investigators also found that samples frozen at -20ºC had significantly higher concentrations of platelet-derived growth factor PDGF-BB, transforming growth factor-β (TGF-β), indicating superior platelet activation. The additional spinning did not appear to enhance the effect. No significant differences were observed among the treatments for vascular endothelial growth factor-A (VEGF-A) or fibronectin, Dr Tiveron noted. Mauro Tiveron Jr, C/O Prof Jorge L Alió: jlalio@vissum.com